1. Field of the Invention
The present invention relates to display devices in which pixel defects can be restored, and is suitably applicable to liquid crystal display devices, in particular.
2. Description of the Related Art
In recent years, as exemplified by a cellular phone, mobile information-terminal devices have rapidly been developing; what are required in these mobile terminal devices are that they are compact and can be driven for a long time. In this situation, among display devices that dissipate electric power most, so-called semi-transmissive display devices have been drawing attention, in which, in a dark environment, display is implemented as usual with a back light, and, in a bright environment, display is implemented by utilizing light from the surrounding environment, in stead of a back light, whereby the power consumption can be saved.
Japanese Laid-Open Patent Publication No. 1999-281992 discloses a semi-transmissive liquid crystal display device in which an interlayer insulating film made of an organic resin film is formed, an unnecessary portion of the interlayer insulating film, such as a drain contact hole, is removed by utilizing the photolithography technology, a transmissive-electrode material is formed, a transmissive electrode is formed by utilizing the photolithography technology to pattern the transmissive-electrode material, thereafter, a reflective-electrode material is formed, and a reflective electrode is formed by utilizing the photolithography technology to pattern the reflective-electrode material.
In the foregoing conventional semi-transmissive liquid crystal display device, the reflective electrode is formed in a layer other than layers for other signal lines; however, the reflective electrode may be formed with conductive film situated in the same layer as those for other signal lines (e.g., the source line) so that production efficiency is enhanced. In the case of a display device such as this, within one pixel, the source line and the reflective electrode are formed with conductive films situated in the same layer; thus, the space between the source line and the reflective electrode should be set to be the same or larger than a predetermined value. In a conventional display device such as this, in the case where, especially in a reflective region formed of a reflective electrode, display based on reflected light is implemented, there has been a problem in that a liquid crystal existing in a space (a region to which no drain voltage is applied; referred to as an ineffective region, hereinafter) between the source line and the reflective electrode deteriorates display quality, for example, by causing light leakage of a back light, due to abnormal orientation caused by no desired voltage being applied to the liquid crystal, thereby deteriorating the contrast, and by causing defective display due to an unintentional voltage being applied to the liquid crystal. In order to prevent such deterioration of the display quality, the problem has been treated, for example, by expanding a transmissive electrode in a transmissive region and providing the transmissive electrode in the vicinity (ineffective region), of the source line in the reflective region, that causes the light leakage.
However, in general, the expanded portion of the foregoing transmissive electrode is often arranged on the top layer of a substrate, and, in that case, the expanded portion is arranged also in the reflective region; therefore, in the case where an opposing substrate (color filter substrate) is attached that is provided in such a way that a liquid crystal layer is sandwiched between the opposing substrate and the insulating substrate, the space between the opposing substrate and the expanded portion of the transmissive electrode in the reflective region becomes narrower than other portions. Accordingly, there has been a problem in that, in the case where a foreign material or the like is sandwiched between the insulating substrate and the opposing substrate, the foreign material creates a short-circuit between the transmissive electrode in the topmost layer in the reflective region on the insulating substrate and the opposing substrate, whereby the probability of a point defect is raised.